Starch gelatinization under pressure studied by high pressure DSC

Published Date
Received 26 May 2008, Revised 30 July 2008, Accepted 31 July 2008, Available online 9 August 2008.

Author
Hongsheng Liu. Author links open the author workspace.a. Numbers and letters correspond to the affiliation list. Click to expose these in author workspaceb. Numbers and letters correspond to the affiliation list. Click to expose these in author workspacec. Numbers and letters correspond to the affiliation list. Click to expose these in author workspaceLong Yu. Author links open the author workspace.Opens the author workspaceOpens the author workspaceb. Numbers and letters correspond to the affiliation list. Click to expose these in author workspacea. Numbers and letters correspond to the affiliation list. Click to expose these in author workspaceKatherine Dean. Author links open the author workspace.b. Numbers and letters correspond to the affiliation list. Click to expose these in author workspaceGeorge Simon. Author links open the author workspace.c. Numbers and letters correspond to the affiliation list. Click to expose these in author workspaceEustathios Petinakis. Author links open the author workspace.b. Numbers and letters correspond to the affiliation list. Click to expose these in author workspaceLing Chen. Author links open the author workspace.a. Numbers and letters correspond to the affiliation list. Click to expose these in author workspace

a

Centre for Polymers from Renewable Resources, ERCPSP, SCUT, Guangzhou, China

b

CSIRO, Materials Science and Engineering, Gate 4, Normanby Road, Clayton South, Melbourne, Australia

c

Department of Materials Engineering, Monash University, Melbourne 3169, Australia

Abstract
The gelatinization process of waxy corn starch under different pressures up to 10.0 MPa was investigated using a high pressure DSC. Compressed air and carbon dioxide were used as pressure resources. Effect of pressure and annealing under pressure on gelatinization of waxy corn starch was systematically studied, in particular on the gelatinization temperature and enthalpy. The results show that the peak temperature of gelatinization was increased slightly initially then remained stable with increasing pressure. The gelatinization enthalpy was decreased under pressure processing. Annealing the starch under pressure condition, just below its gelatinization temperature, increased gelatinization temperature but kept gelatinized enthalpy constant. Morphologies of starch granules treated under pressure were studied using an optical microscope and SEM. There is no discernable difference of starch granules treated with and without pressure, which indicates the pressures are not high enough to destroy crystalline structure. The intensity of the pressure acts as a key factor to influence the gelatinization of starch rather than the nature of the gas. Effect of pressure on the multi-endotherm detected by DSC for starch with intermediate water is used to study the mechanisms. The effect of pressure can be explained by the enhancement of water diffusion in the amorphous range.

Keywords

Starch

Gelatinization

DSC

Pressure

Annealing

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